#!/usr/bin/env python3
import os
import datetime
import requests

import csv

import xarray as xr

import numpy as np

from metpy.units import units
import metpy.calc as mpcalc

from .. import misc

def get_current_run():
    date=(datetime.date.today() - datetime.timedelta(days = 1)).strftime('%Y-%m-%d')
    # TODO we also want noon
    hour='23:00:00'
    return (hour, date)

def download_wyoming_csv(station, date, hour, target):
    url=f'http://weather.uwyo.edu/cgi-bin/bufrraob.py?datetime={date}%20{hour}&id={station}&type=TEXT:CSV'
    result = requests.get(url)

    if result.status_code >= 400:
        raise Exception('Failed to Download sounding csv!')

    with open(target, 'w') as f:
        f.write(result.text)

def load_wyoming_csv(filepath, hour, date):
    p = []
    T = []
    Td = []
    wind_speed = []
    wind_dir = []
    r = []

    with open(filepath,'r', newline='') as f:
        reader = csv.reader(f)
        next(reader) # Skip header
        for row in reader:
            if sum(map(lambda s : len(s.strip()) == 0, row)):
                # skip any line with empty values
                continue

            if float(row[3]) in p: # Skip double p entries
                continue

            p.append(float(row[3]))
            T.append(float(row[5]))
            Td.append(float(row[6]))
            r.append(float(row[8]))
            wind_speed.append(float(row[12]))
            wind_dir.append(float(row[11]))

    T = T * units.degC
    Td = Td * units.degC
    wind_speed = wind_speed * units.knots
    wind_dir = wind_dir * units.degrees
    u, v = mpcalc.wind_components(wind_speed, wind_dir)

    time = np.datetime64(f'{date}T{hour}')

    # recreate the structure a DWD GRIB produces
    return xr.Dataset(
        {
            "t": (["step", "isobaricInhPa"], [T.to(units.kelvin).magnitude]),
            "td": (["step", "isobaricInhPa"], [Td.to(units.kelvin).magnitude]),
            "r": (["step", "isobaricInhPa"], [r]),
            "u": (["step", "isobaricInhPa"], [u.to('m/s').magnitude]),
            "v": (["step", "isobaricInhPa"], [v.to('m/s').magnitude]),
        },
        coords={
            "isobaricInhPa":  p,
            "step": [np.timedelta64(0, 'ns')],
            "valid_time": (['step'], [time]),
            "time": time,
        },
        attrs={
            "source": "uwyo.edu",
        }
    )

def load_data(name, output, station):
    hour, date = get_current_run()
    misc.create_output_dir(output)

    target = os.path.join(output, f'{name}_{date}_{hour}.csv')

    if not os.path.exists(target):
        download_wyoming_csv(station, date, hour, target)
    else:
        print(f'{target} alreasy exists. Using the cached version.')

    return load_wyoming_csv(target, hour, date)

config_debug = {
    'output': 'wyoming_test',
    'station': '10548'
}

if __name__ == '__main__':
    ds = load_data('test_wyoming_sounding', **config_debug)
    print(ds)
    print(ds.coords['step'])